Had a search through to make sure it wasn't covered already. Had my air con debugged by local Mr T last Friday (it was smelling), advised them of the air con occasionally blowing normal air and not ice cold but they didn't sort this as there was a mix up with what they were supposed to do so its going back in for the gas refill. I have noticed that occasionally I get a 3 second blast of white smoke when I first turn my air con on. Been like this for a few weeks but thought nothing of it due to the booking to have the de-bug done. Today I tested it again and everytime I turned my air con on (4 times I tried it) the white smoke blasted out for 3 seconds and then disappeared. What is this white smoke? Kinda worrying me a bit as first time I saw it I thought my engine was on fire. Never had this problem with any other car when the gas runs out before!

This is on my T Sport corolla.

Any advice please. Is it blowing out the last remains of the gas which is the white smoke?

When I get Mr T to re-gas is that all they need to do and check? Or should they check something else with the pipes etc when they re-gas?

Sorry, no; never heard of such a thing happening, and can't think what could possibly cause it.

You say smoke - that implies something's burning - or could it be just dust particles that have settled in the air vent, or the release of some gas from the air con system itself? Probably not the dust particles - not if it happens repeatedly I guess. If it's gas esscaping then your re-charge won't last long?

Apart from that, it would have to be an electrical problem to cause smoke and no flames I would think?

Sorry, that's all wild speculation - just trying to think of what could possibly cause such a strange problem. I'll be interested to hear what the real answer is once you figure it out.

i had it on my hilux after running the aircon for a long while, turned it off, and back on and all was fine, i just think it was because the air was very cold......its never done it since

Thanks for both of your comments.

Its strange as it will do it as soon as I turn the air con on regardless if its been on previously or not. I don't think its because its very cold as I have never had that in any air con car before and its not constant cold at the moment (hence the re-gas).

I will speak to Mr T tomorrow as its due for a re-gas on Saturday so want to prepare them to investigate in more detail. Its under Toyota warranty so any problems with the air con unit will be covered. They don't exclude air conditioning under the full warranty do they? Hope not.

Ok. Spoke to Mr T today and they haven't heard of this before (which I find hard to believe, but they would say that!)

Did a deeper search and found some results on MG and Honda sites and this is what they say;

Personally I haven't heard of any of them before and I have never had any issues with previous cars with A/C in hot/cold weather so I am not convinced its a weather problem causing it to blow white smoke.

"Its condensed water vapor. The humid outside air is being lowered beyond its dew point by the A/C evaporator, and some of it is being blown past as condensed water vapor (fog) through the vents for a few moments before it begins to stick to the evaporator, where it normally collects and drips off."

"the 'smoke' that is coming from the air conditioning vents is a normal condition and nothing to be concerned about. It is essentially the cold air that is being blown out of the vents causing the warm moist air inside the car to condense. It is the same thing that happens when you open a refrigerator freezer and blow the warm air from your lungs into the freezer, or, why you can "see your breath" on a cold day, or for that matter, the same reason that clouds form in the sky.

the condition is more noticable on very humid days and I would venture to guess that the "problem" goes away after driving the car for a few minutes as the interior cools down.there is absoluetly nothing to be done to 'fix' this normal condition."

"probably just fog. When you go to recirc, the fresh airflow over the A/C cooler/evaporator is suspended so the surrounding air (which contains water vapour) will chill to a much lower temperature, so producing fog. When you switch back to air flow, the fog is blown out the vents. "

"Most likely the heater core is leaking. If there is also water on the floor and an antifreeze smell in the passenger compartment, those are also signs of a cracked heater core. Also, GET THAT TEMP GAUGE FIXED!!! You could be overheating and not even know it. Once the motor overheats, you're risking a blown head gasket, a VERY EXPENSIVE repair, or even worse, a blown engine. If steam is coming out of the vents it is very possible the motor is overheating. You need two repairs, your heater core and your temperature gauge. "

I had that in my E11 a little bit - but I've only ever noticed it about 5 times in the last 4 years. It just looks like a light white fog being blown out of the air vents, and would occur usually during an entire journey (with the air con on of course!). I guess the important thing to note is that it only ever happened when it was hot (ie. above 25 degrees outside temp) and very humid outside. Didn't seem to affect the cooling of the air con and it didn't seem to affect me adversely (no smell either), so I never worried about it, and assumed it was air moisture related. I've also occasionally seen my own breath inside the car when its very sunny outside and the air con is on (think it was on recirc mode, hence was probably colder than normal).

Since your air conditioner's cold radiator (the one inside the dashboard) is having air blown across it from either outside or recirculated from inside the car, it does make sense that if you blow moist, warm air across the air con rad, some of it might not condense fully onto the cold rad at that point as water, but might just be cooled to the all-most condensed transitional form known as mist or fog, which would then come out of the air vents looking like white smoke, before quickly being warmed up by the rest of the air in the car, causing it to disappear as the water suspends fully in the air again.

It should be quite easy to test if this is the case for you, by taking the car out at night when it's cooler outside, and seeing whether you still get the effect. Also, having a think about it, if you run the A/C in recirc mode for a while, then it should dry out the inside air quite a lot - turning the air con off at this point for a couple of minutes and then firing it up again would therefore not be likely to give you the smoke effect (if its water vapour related).

If so then probably nothing to worry about, though I'd have thought your air con would have to be extremely effective for that to happen.

I did notice the other day that I was breathing cold vapour when it was very cold in the car and hot outside. It might be this but its just I have never seen this happen before on any of my cars. Doesn't do it in the Yaris T Sport we've got! Will still get Mr T to check the hoses.

I had that in my E11 a little bit - but I've only ever noticed it about 5 times in the last 4 years. It just looks like a light white fog being blown out of the air vents, and would occur usually during an entire journey (with the air con on of course!). I guess the important thing to note is that it only ever happened when it was hot (ie. above 25 degrees outside temp) and very humid outside. Didn't seem to affect the cooling of the air con and it didn't seem to affect me adversely (no smell either), so I never worried about it, and assumed it was air moisture related. I've also occasionally seen my own breath inside the car when its very sunny outside and the air con is on (think it was on recirc mode, hence was probably colder than normal).

Since your air conditioner's cold radiator (the one inside the dashboard) is having air blown across it from either outside or recirculated from inside the car, it does make sense that if you blow moist, warm air across the air con rad, some of it might not condense fully onto the cold rad at that point as water, but might just be cooled to the all-most condensed transitional form known as mist or fog, which would then come out of the air vents looking like white smoke, before quickly being warmed up by the rest of the air in the car, causing it to disappear as the water suspends fully in the air again.

It should be quite easy to test if this is the case for you, by taking the car out at night when it's cooler outside, and seeing whether you still get the effect. Also, having a think about it, if you run the A/C in recirc mode for a while, then it should dry out the inside air quite a lot - turning the air con off at this point for a couple of minutes and then firing it up again would therefore not be likely to give you the smoke effect (if its water vapour related).

Good luck figuring it out - let us know how you get on!

Thanks for your details reply. Didn't happen at all today, tried to replicate but no smoke! I hope it is what you and others have been saying about the difference in temperature for this to happen. Still going to get Mr T to check the hoses when it gets re-gased on Saturday. I will try either tonight or tomorrow night when its cool outside and take her for a spin with the A/C on and see what happens. If nothing happens and Mr T doesn't find any issues then will leave it. I can always try and see if it happens in autumn/winter as it will still be under warranty so if there is a problem with the A/C Mr T will have to repair it. Will let you know how I get on. Thanks.